Bushnell 78-9540 Telescope User Manual


 
UNDERSTANDING THE EQUATORIAL MOUNT
The Equatorial Mount (5) is designed to move in any direction. It can be set to allow
manual controls to track the movements of celestial bodies across the sky. This is
referred to as diurnal movement; movement of celestial bodies in the direction
opposite to that of the earth’s rotation and is around the earth’s axis.
By aligning the telescope’s polar axis at celestial North, you will place the
telescope in parallel with the earth’s axis and thus be able to locate stars in the sky
based on star atlas information. To compensate for your position on earth, the
polar axis is set in one of three ways:
Set up the telescope at night. Loosen the Declination Lock Knob (12) and rotate
the telescope around the declination axis until the arrow on the declination
scale points to 90 degrees. Tighten the Declination Lock Knob. The telescope is
now roughly in parallel with the polar axis.
Loosen the Horizontal Axis Lock Knob (13) and turn the telescope until the
objective end faces due north. This can be done by approximating the location of the pole star (Polaris or
North Star) or by the use of a compass. True North is then found by directing the telescope at Polaris, as
magnetic North is slightly away from true North.
Look up the latitude of your area in any geographical atlas. Loosen the Latitude Lock Knob and set the
latitude scale to the correct latitude for your area. Aim the Finderscope (7) at Polaris. You will probably
notice that Polaris is not dead center in the Finderscope’s field of view. This is probably because your
telescope is not absolutely level with the ground. Loosen the Horizontal Axis Lock Knob (13) again and
turn the telescope so that it is directly aimed at Polaris. Tighten both the Horizontal Axis Lock Knob and
Latitude Lock Knob. Polaris is 1 degree from the North celestial pole. Therefore, the sighting of stars will
have to be slightly adjusted as you locate them in the heavens.
Never Look Directly At The Sun With Your Telescope
Permanent Damage To Your Eyes May Occur
Enjoying Your New Telescope
1. First determine your targeted object. Any bright object in the night sky is a good starting point. One of the
favorite starting points in astronomy is the moon. This is an object sure to please any budding astronomer or
experienced veteran. When you have developed proficiency at this level, other objects become good
targets. Saturn, Mars, Jupiter, and Venus are good second steps to take.
2. The first thing you need to do after assembling the telescope as planned is center the desired object in the
finderscope's cross hairs. Provided you did a reasonable job aligning the finderscope, a quick look through
the main telescope tube at low power should reveal the same image. With the lowest power eyepiece (the
one with the largest number printed on it) you should be able to focus the same image that you saw through
the finderscope. Avoid the temptation to move directly to the highest power. The low power eyepiece
will give you a wider field of view, and brighter image--thus making it very easy to find your target object.
At this point with a focused image in both scopes, you've passed the first obstacle. If you don't see an image
after attempting to focus it in, you might consider aligning your finderscope again. Once you pass this step,
you'll will enjoy the time spent ensuring a good alignment. Every object you center in the finderscope will be
easily found in the main telescope tube, which is important for continuing your exploration of the night sky.
3. The low power eyepieces are perfect for viewing the full moon, planets, star clusters, nebulae, and even
constellations. These should build your foundation. However, for more detail, try bumping up in
magnification to higher power eyepieces on some of these objects. During calm and crisp nights, the
light/dark separation line on the moon (called the "Terminator") is marvelous at high power. You can see
mountains, ridges and craters jump out at you due to the highlights. Similarly, you can move up to higher
magnifications on the planets and nebulae. Star clusters and stars are best viewed through the low power
no matter what.